def str_reverse(s):
    """反转字符串s"""
    return s[::-1]
def substr(s, x, y):
    """
    按照给定的下标切分字符串
    :param s: 字符串
    :param x: 开始下标
    :param y: 结束下标
    :return: 切片后的字符串
    """
    return s[x:y]
if __name__ == '__main__':
    print(str_reverse("一二三四五"))
    print(substr("一二三四五",1,3))